February 27, 2007—Indonesian officials have begun dropping
concrete balls into a devastating upwelling of mud in a novel but
controversial plan to plug up the disaster.

On Monday engineers on the island of Java successfully released the first 16 of the balls into the "mud volcano," which has left more than 11,000 homeless, ruined miles of countryside, and killed at least 13 since it began erupting nine months ago.

Over the next few weeks the team plans to drop a total of 1,500 concrete spheres, weighing up to 90 pounds (40 kilograms) each, in an attempt to stanch the flow of mud.

Mud volcanoes occur when pressure deep within the Earth forces mud through the surface. They are often triggered by earthquakes, but a study led by earth scientist Richard Davies published in January says that this upwelling was human-caused, beginning when an exploratory gas well pierced an aquifer of hot, high-pressure water.

The plan to plug the volcano is based on the assumption that the mud vent looks like the neck of an hourglass, said Davies, of England's Durham University. Indonesian experts hope the balls will form a snug fit, increasing the amount of friction the mud experiences and slowing or stopping its flow.

"This has never been attempted before that I am aware," Davies said. "Nobody's ever tried to stop a mud volcano."

But "the most likely possibility is that nothing will happen at all," he added, because the actual shape of the vent is likely to be far more complicated than a simple circle.

What's more, disaster could loom if the plug holds, because pressure will continue to build up in the area.

A more practical solution, he said, is to determine how long the volcano will last and engineer an appropriate solution. Some of the mud is being bottled up behind temporary dams, but concrete barriers might be necessary instead.